This patent application relates to devices and methods for detecting whether a device is indoor or outdoor.
Methods to detect whether a device is indoors versus outdoors have undergone impressive improvements in recent years. However, current approaches have certain weaknesses: many approaches rely on a Global Positioning System (GPS) or Global Navigation Satellite System (GNSS) receiver or a light sensor, which may fail in certain situations. FIG. 1A illustrates a mobile device 110 in which a GPS receiver 111 receives GPS signals 121, 131 from satellites 120, 130, when mobile device 110 is outdoors, such as a farm 101. Mobile device 110 includes an indoor versus outdoor detector 112 (also called an indoor-outdoor (IO) detector) coupled to GPS receiver 111. IO detector 112 may use a drop in confidence or inability to obtain a fix by GPS receiver 111 as a cue to infer that mobile device 110 is indoors, e.g. in a shopping mall 110 as shown in FIG. 1B. However, when mobile device 110 is near a window of a building, IO detector 112 may get a GPS fix although mobile device 110 is indoors, which makes this method unreliable.
The inventors of the current patent application recognize that methods, devices, apparatuses, systems, and computer-readable storage media of the type described below can detect whether a user is indoor or outdoor in a more reliable manner.